Amazon has fired customers before for making too many returns[0]. So be aware that this may get your account banned at some point.
Have you seen an instance of this happening to someone who did not return multiple large purchases? I am worried about this happening, but in every instance I read about, the person who got banned had returned multiple TV's or computers, not small items. However, the ebook return policy has only been in place for around a year, so it might not show up.
With ebook returns, it seems like they only disallow you from refunding ebooks in the future, but do not ban your account
Thus spake Eliezer:
It seems that many here might have outlandish ideas for ways of improving our lives. For instance, a recent post advocated installing really bright lights as a way to boost alertness and productivity. We should not adopt such hacks into our dogma until we're pretty sure they work; however, one way of knowing whether a crazy idea works is to try implementing it, and you may have more ideas than you're planning to implement.
So: please post all such lifehack ideas! Even if you haven't tried them, even if they seem unlikely to work. Post them separately, unless some other way would be more appropriate. If you've tried some idea and it hasn't worked, it would be useful to post that too.